What Causes Dry Lightning?
KPIX 5 Morning Weather Anchor Roberta Gonzales answers the questions you never get to ask on-air.
Q: Hey Roberta, I keep hearing you talk about "Dry Lightning." Tell me more. - David Sanchez, San Leandro
A: Would love to! Thanks for asking David!
The term, "dry lightning" is used when lightning is occurring without significant precipitation. If you think about it, the "dry" lightning is a bit redundant, because last time I checked, lightning is not wet. But everyone uses the term because it is so descriptive!
Here in California and in western states, we should be very mindful of dry lightning because it is the cause of wildfires each year, some of which grow to be dangerously large.
In a normal thunderstorm, lightning strikes while rain falls from the storm clouds, usually accompanied by the sound of thunder. When the lightning hits the ground, it may cause a spark of flame, but the rain which comes down with the lightning puts the fire out before it has a chance to spread. In a dry storm, rain is produced, but it never reaches the ground. That's called "virga."
What causes the dry lightning? In many western states, storms tend to form extremely high, which means that the rain may pass through a huge zone of warm air on its way to the ground. The dry, warm air causes the rain to evaporate. These storms are also often accompanied by dry microbursts, gusts of cold air which rush down from the clouds and spread rapidly when they hit the ground, causing gusty winds at the surface of the Earth.
I would love to hear from you! Please send weather questions, observations and photos to me, Gonzales@kpix.cbs.com and I look forward to hearing from you!
